(i) Field to which the invention relates
The present invention is with respect to an automatic reel change system for use in connection with the processing of a web, coming from one reel in a reel support, the web being sheeted in a transverse cutter.
(ii) The prior art
German Pat. No. 2,010,467 has an account of a system for processing a web which is sheeted in a transverse cutter and is taken from a reel. In this prior art system, the reel support is only designed for one reel at a time. When the reel has run to an end, an new reel has to be placed in position and the web threaded in again, a complex and time-taking operation causing drop-outs in production and generally increasing the running costs of the plant.
In the web-feed, rotary press art automatic reel change makes continuous operation possible. In old systems of this sort (see for example German Offenlegungsschrift specifications Nos. 2,246,360 and 2,331,125) a "reel" (short for reel stand) is used for supporting a number of reels at the time and having a frame with a horizontal axle with spokes radiating from the hub near each end and horizontal bars or slats connecting these in pairs. When stock is running to an end on one reel, the next, new reel is speeded up to the running speed by a separate driving unit. For joining the web, which is coming to an end on the old reel to the next web, taken from the new reel, the old web is pressed against the new reel and joined to it by paste placed in the space between the webs or present on one of them. After joining the old web is cut out. In system of this sort, it will be seen that there is a generally long overlap, in which the web will have twice its normal thickness. In web-feed presses, such a thicker part of the web may be put up with, but this is not so with sheet-feed presses which are much more likely to be damaged. For this reason, the overlapped web part has to be taken out of the flow of stock through the system using parts for sensing its position; however, the flow of stock is then interrupted and, necessarily, production is stopped and has to be started again. This would seem to be the reason why, so far, sheet-feed machines using webs (that is to say having a sheeter-feeder) have not been designed for automatic reel change.